5 Warning Signs You Have an Underground Water Leak

Most homeowners assume that if they cannot see a leak, there is not one. But underground water leaks can run for weeks or even months before any visible damage appears, silently driving up your water bills and undermining the ground beneath your property.

At Enviro Leak, we deal with underground water leaks across the North East every week. Here are five of the most common warning signs that tell us a property has a hidden leak, and what you should do if you spot them.

1. An Unexplained Rise in Your Water Bill

This is often the very first clue. If your household water usage has not changed but your bill has crept up steadily over the past couple of quarters, there is a strong chance that water is escaping somewhere between your stop tap and your property. Even a small crack in an underground supply pipe can waste thousands of litres per month. Compare your recent bills side by side — a consistent upward trend with no obvious explanation is worth investigating.

2. Low Water Pressure Throughout the Property

A sudden or gradual drop in water pressure, particularly across multiple taps and outlets rather than just one, can indicate that water is leaving the system before it reaches your fixtures. This is especially telling if your neighbours on the same supply are not experiencing the same issue. Read more about why low water pressure could point to a supply pipe problem.

3. Damp, Soft or Sinking Areas in Your Garden

Underground supply pipes typically run beneath driveways, paths and garden areas. When they leak, the water saturates the surrounding soil. You might notice patches of ground that feel unusually soft or spongy underfoot, areas of grass that are greener and lusher than the rest of the lawn, or sections of a driveway or path that appear to be sinking or cracking without any obvious cause. In winter, you might even spot patches of ground that thaw faster than the surrounding area because of the warmer mains water below.

4. The Sound of Running Water When Nothing Is On

If you can hear a faint hissing or rushing sound when all taps, appliances and heating systems are switched off, that is a significant red flag. Stand near your internal stop tap or water meter and listen carefully. Underground leaks on pressurised supply pipes create a constant noise as water escapes through the crack or joint failure. This is also the principle behind the acoustic correlation technology we use at Enviro Leak to pinpoint leak locations with precision.

5. Your Water Meter Is Still Turning

This is a simple but effective test you can carry out yourself. Turn off every tap, appliance and water-using device in your property. Make sure the central heating is off and no toilets are filling. Then check your water meter. If the dial is still moving, water is leaving the system somewhere. Repeat the test after 30 minutes and note any change in the reading — any movement at all confirms a leak on your side of the supply. Our step-by-step guide to using your water meter to check for a leak walks you through it in detail.

What to Do If You Spot These Signs

If one or more of these warning signs applies to your property, the worst thing you can do is ignore it. Underground leaks do not fix themselves. They worsen over time, and the longer they run, the greater the damage to foundations, drainage systems and the surrounding ground.

At Enviro Leak, we use advanced non-intrusive leak detection and underground leak detection to pinpoint the exact location of leaks without any digging or disruption. This saves you time, money and unnecessary damage to your property. Not sure whether the leak is underground or inside? Our guide to telling the difference can help.

We offer free initial assessments across the North East, so there is no risk in getting it checked.